No, the C602 motherboard does not support the Xeon E5-2689 processor.
No, the C602 motherboard does not support the Xeon E5-2689 processor.
The seller didn't mention it, and I'm not interested in purchasing just a Ryzen because I already own a used Xeon Core without a board.
Many branded boards like Dell and HP include a whitelist for compatible CPUs. If it’s not listed, you should assume it won’t work, regardless of chipset support. Without the exact motherboard model, we can only make an educated guess.
Guy seems suspicious, so I'll hold off on this next opportunity.